Radiation Therapy (RT) as a Chemosensitizer of Gemcitabine (G) in Patients with Metastatic/Unresectable Tumors of the Gastrointestinal (GI) Tract - a Phase I/II Study Exploring a New Treatment Paradigm

Reviewer: Christopher Dolinsky, MD
University of Pennsylvania School of Medicine
Last Modified: October 19, 2005

The median survival for all 10 patients is 10 months (range 4-37 months).

Based on radiographic definitions, 1 patient had a complete response, 2 had partial responses, 5 had stable disease, and 1 had progressive disease.

Author's Conclusions

LD-UART was well-tolerated at the 60 cGy level when combined with gemcitabine.

Given the encouraging radiographic responses and median survival of 10 months in this poor-prognosis group of patients, continued phase II evaluation of this regimen is warranted.

Clinical/Scientific Implications

This is a fascinating piece of research that explores a truly novel treatment paradigm. The investigators, based on work performed in the laboratory, moved a new principle into the clinical arena. The idea that low-dose radiation therapy can serve as a chemosensitizer has not been widely tested in clinical medicine. As each of the study patients has such a large volume of disease, it would not be safe to deliver high-dose radiation concurrently with full- strength gemcitabine chemotherapy. Another research group who presented their work at this year's meeting is testing the exact opposite paradigm, using low-dose gemcitabine to act as a radiosensitizer for standard-dose abdominal radiation.

All of the patients in this study, based on their disease presentations, have extremely low chances of achieving lengthy survival outcomes using the current standard of medical care. The finding that 9/10 patients had at least radiographically stable disease is quite remarkable. The authors should be commended for undertaking this interesting and promising research. In the future, phase II and III data utilizing this regimen will help us to determine whether this is actually the most effective treatment strategy for this subgroup of patients with unfavorable prognosis.